Quinn is an engaging Celtic surname, zippy, concise and strong. While it may now lean feminine in the US, given to girls about 80% of the time, it is still given to a substantial number of boys: 615 in a recent count.

Flynn, a charming Irish surname, is still used only quietly, despite its easygoing, casual cowboy charm, unlike Finn which is a star of this genre. Flynn was the choice of Orlando Bloom and Miranda Kerr for their baby boy, and is also the middle name -- used as his first -- of a son of Miranda's fellow supermodel Elle Macpherson, of Gary Oldman's son Gulliver and Marley Shelton's daughter West.

Callahan, the simpler spelling of Callaghan, is a rhythmic jig of a name whose history harks back to the ancient King of Munster. In the Dirty Harry movies, the Clint Eastwood character is Harry Callahan.

Leif is one of the most recognizable Scandinavian names, thanks to Icelandic explorer Leif Erikson, and is still one of the best, with a pleasant aural association with the word leaf.

In the past few years Ellery has gone from middle-aged male detective -- from old school fictional hero Ellery Queen -- to a plausible girls' name, a la Hillary.

Brenna is a feminine form of the Irish surname Brennan, or perhaps a variation of Brenda or Brendan—all of which have different meanings. Whatever its derivation or authenticity, it's a modern sounding name which has steadily decreased in popularity since 1995 when it peaked at Number 235 in the United States.

Troy shot to popularity as a first name in tandem with that of 1960s heartthrob Troy (born Merle) Donahue; its image has now, thanks in part to the Brad Pitt-starring epic, Troy, receded back to conjuring up the ancient site of the Trojan wars.

This evocative green nature name, heard much more frequently as a surname, is associated with playwright Moss Hart (born Robert), who co-wrote (with George S. Kaufman) such enduring Broadway comedies as The Man Who Came to Dinner and You Can't Take it With You.

A winning last-name-first Celtic choice, Flynn is still mostly used for boys, such as the son of Orlando Bloom and Miranda Kerr. Though Flynn is definitely one of the Irish surname names, from Quinn to Flannery to Makenna, that makes one of the trendy boy names for girls".

Ellery is a rhythmic three-syllable boy's name that is familiar and yet rarely used--and just waiting to be discovered. It's long been identified with Ellery Queen--which was both the pen name of two cousins, Frederic Dannay and Manfred B. Lee, and the detective they created.

Modern way to honor an ancestral Hugh.

Long before the vogue of using Irish surnames for girls, writer Flannery O'Connor gave this one some visibility. It has a warm (flannelly) feel and the currently popular three-syllable ee-ending sound.

Gallagher is, like so many of its genre, friendly, open, and optimistic. Some might associate it with the fraternal members of the band Oasis, Noel and Liam Gallagher.

Halloran could be your solution if you love the nickname Hal, but not Harold or Henry.

Although it looks like an English placename, the surname Crowley is an anglicization of the Irish O Cruadhlaoich. A famous bearer was the occultist Aleister Crowley, and it also appears on characters in Supernatural and The Walking Dead. It has started to get a little use in recent years, as part of the new wave of names ending in -ley.

Americans may consider Lohan a surname name forever tied to Lindsay but in France, it's a modern variation of the Breton saint's name Elouan.

Flann variation that's most familiar as the name of writer Flannery O'Connor. It derives from the Irish surname Ó Flannghaile, meaning "descendant of Flannghal".

Tierney is a Celtic surname with a definite Irish twinkle, a name just waiting to be discovered. Though now sometimes used for girls (in the US, not Ireland), as in jazz singer Tierney Sutton, it still has plenty of masculine punch.

This two-syllable Irish surname is as appealing as Nolan, Keegan et al, but much less common.

Associated with iconic British designer and retailer Terence Conran, who had an international impact on household design. Makes a nice variation on Conrad.